1. Field of the Invention
The present invention relates to a jump-starting method and a device for implementing the method and a device for implementing the method.
2. Description of Related Art
A conventional motor vehicle normally includes a combustion engine for the motive power and at least one battery for storing electrical energy. In the case of a breakdown, for example, in the case of a discharged or only weakly charged battery, the broken-down vehicle may be rendered operational again in a relatively simple manner, by a jump-start from another motor vehicle. To that end, the electrical systems of the two vehicles are interconnected by a two-pole jumper cable. In this connection, it must only be made sure that the electrical system voltage of the two vehicles is the same and the vehicle providing the jump-start can supply the necessary power of approximately 1-5 kW to start the combustion engine of the broken-down vehicle. When the engine is running, the discharged battery may then be recharged by the generator. In the case of older vehicles and vehicles not having an automatic transmission, it is even possible to tow-start or push-start them. However, this is different for electric vehicles (hereinafter referred to as EV). These vehicles are designed in such a manner, that normally, they can only be recharged on the power supply system.
From published German patent application document DE 101 10 615 A1, a method for producing control pulses for power semiconductors is known, in particular, for the purpose of generating offset control pulses for half-bridges, which are accommodated on multiphase converters or d.c-d.c. converters. In this method, the reference voltage is shifted by a delay time corresponding to the offsets, or a PWM signal is shifted by a delay time corresponding to the period divided by the number of offsets.
Published German patent application document DE 101 19 985 A1 describes a device for supplying power to a multi-voltage electrical system of a motor vehicle. This device has a multi-voltage electrical system situated in a motor vehicle, which provides at least one first and one second voltage level, in each case, differing from the reference potential. The multi-voltage electrical system is powered from at least one electrical energy store. In addition, it has at least one converter for connecting the two voltage levels. Furthermore, supply means are provided for externally supplying power to the multi-voltage electrical system. The mentioned converter may be implemented in the form of a multiphase converter. In such converters, several converter cells of lower capacity are connected in parallel, and the power circuits are clocked in a time-staggered manner. This saves filter components on account of the effects of destructive interference. Such multiphase converters make it possible to implement the first and second converters, using the available phases of a single multiphase converter. To this end, the phases are split up in a converter having step-down and step-up converter functionality. Inside the converter, the phases are then separated on the input side, via a switch.
From German patent application DE 10 2007 043 603.5, a multiphase d.c.-d.c. converter is known which has a plurality of converter cells that are disposed in parallel to one other and are clocked in a time-staggered manner. In each instance, a magnetic measuring bridge is disposed between the outputs of two converter cells.
Published German patent application document DE 696 17 026 describes a system for charging a battery of accumulator storage batteries of a motor vehicle from a single-phase voltage source, the motor vehicle being equipped with a three-phase a.c. driving motor having three windings, as well as with an inverter having three interrupters for powering the three-phase a.c. motor, means being provided for operating the above-mentioned inverter as an a.c./d.c. voltage converter having a rectifier voltage-increasing stage, which has a first and a second interrupter branch of the inverter, a voltage-decreasing stage having a third interrupter branch of the inverter, and means for connecting the first and second interrupter branches to the single-phase voltage source, and for connecting the center tap of the third interruption branch to the battery for supplying d.c. voltage. In the system, the center taps of the first and second interrupter branches are connected to the above-mentioned single-phase voltage source via a first inductor, which is made up of at least one winding of the three-phase a.c. motor. Furthermore, the center tap of the third interrupter branch is connected to the battery via a second inductor, which is made up of at least one winding of said three-phase current motor, which differs from the winding(s) that form(s) the first inductor.
An electric vehicle or a so-called plug-in hybrid vehicle, i.e., a hybrid vehicle, whose batteries may be charged on the power supply system, normally has at least one three-phase inverter for controlling a three-phase electric motor for the traction of the electric vehicle. Such an inverter may also be used, in cooperation with line inductors, for withdrawing energy from the power supply system, or to feed energy into the power supply system. This is also known from elevator drives or crane drives, for example. In this connection, the intermediate circuit is first charged slowly, via a precharge contactor having resistors, to a voltage just above the rectified system voltage, and then the inverter is used as a step-up converter, which rectifies the three-phase network current or inverts the direct current in the intermediate circuit into a three-phase current system. In the known applications, the system currents are set by the inverter on the basis of the voltage deviation in the intermediate circuit from a setpoint value, and possibly on the basis of a load current, as well. However, for use as a battery charging device, a different type of control of the inverter must be implemented, since in this case, the battery charging current is the desired quantity to be set, and not the desired intermediate circuit voltage.